Patent GB-191223057-A (GB)
Title: Improvements in and relating to the Furnaces of Steam Generators and other Furnaces.
Inventor: SCHLEYDER KARL
IPC: F23L9/00
Filed: 1912-10-09
Granted: 1913-04-03
Abstract: 23,057. Schleyder, K. Oct. 10, 1911, [Convention date]. Blast apparatus; doors. -Relates to fire-door apparatus of the type in which air under pressure is discharged from a nozzle, at the same time drawing the furnace gases to the front of the furnace. A funnelshaped channel, having an inlet of large area facing towards the furnace, and a narrow outlet under the influence of the blast, is provided, into which the gases are drawn to heat the air ; a regulating-device is also provided to vary the intensity of the blast on closing the door. In the form shown in Figs. 2, 3, and 4, the air, supplied under pressure from the pipe 1, passes through an automatic regulator A to the heating-chamber B, which takes the form of an arch secured to the inside of the furnace front and divided by a partition 3, around which the air flows, finally leaving by way of the hollow door hinge E. From thence the air passes by a passage e to a chamber F on the inner side of the fire-door D, and then by channels f to a curved chamber g, situated between the chamber F and the door wall 7. The chamber g terminates in a slit-shaped ejector orifice 10, which can be regulated by a valve 8 adjusted by a set-screw 9. A funnel-shaped chamber h extends around the chamber F and ends in a slit-shaped orifice 11 beneath the orifice 10. An air-supplying channel i, the entrance to which is regulated by a damper 13, runs behind the chambers h, g to the orifice 12. The orifices 10, 11, 12, of equal width and parallel to one another, open into the expanding nozzle 14. The suction caused in the chamber h by the air passing through the ejector orifice 10 causes a portion of the furnace gases to be drawn towards the furnace front, where they take an almost vertical direction and so become intimately mixed with the air blast, while at the same time they impinge on the airheating chambers B, F. An additional air supply is also drawn through the channel i. The regulator A consists of a casing 17 with the air-supplying channel a through it. A lower piston 19 is connected by linkage 22<a>, 23 to the lower door hinge G so as to be raised when the door is opened, when it closes the channel a and cuts off the air supply. At the same time it raises the upper piston 18 to the position shown in Fig. 4. On closing the fire-door, the piston 19 falls, and the piston 18 gradually descends under the action of the spring 20, controlled by the dash - pot 21. While the piston moves from y to z the full blast is admitted to the furnace to compensate for the decreased air supply through the fire-bars consequent upon the introduction of fresh fuel. On further descent, the piston 18 gradually diminishes the air supply until its end 25 contacts with the part 26 of the piston 19. The minimum air supply can be regulated by adjusting the nuts 27 on the piston-rod 22, which raises or lowers the piston 19. In a modification, having the same construction of fire door, chambers, and passages as that already described, the air is supplied by a steam-ejector apparatus, and is regulated by controlling the steam supply to the ejector. The ejector H, Figs. 6 and 7, delivers the air and steam to the chamber B, as before, and consists of a casing 29 with two or more nozz'es 31. The steam supply is controlled by a needle valve M, which is actuated by the firedoor through a rod 37 connected to a crank pin on the lower hinge. When the door is opened, the lever 38 actuates through a ratchet 39 the angle lever 40, 41 which draws the needle 35 from its seat. At the same time a plug valve mounted so as to rotate with the upper hinge of the door, and in the steam pipe 33, is closed, so stopping the steam supply to the ejector and hence the air supply to the furnace. The door being closed, the valve in the pipe 33 is opened while the valve M gradually closes, the rate being controlled by the dash-pot 42, and the minimum opening by the nut 45. In another arrangement, illustrated in Fig. 13, in which the steam-ejector apparatus is combined with the fire-door, a series of nozzles 55 on a pipe 54 deliver the steam to the nozzles 49, which occupy the whole width of the door. Air is thus drawn through the casing 51, the supply being controlled by a damper 52 and delivered to the furnace. At the same time, furnace gases are drawn in through channels 50, the gases taking an upward direction towards the front of the furnace and so crossing the path of the air. The supply of steam to the jets 55 is controlled by two valves in a similar way to that described in the last modification. The Specification as open to inspection under Section 91 (3) (a) comprises also an air -supply chamber arranged in front of the fire-bridge and containing an air-supply nozzle having a slotted orifice extending for nearly the whole length of the bridge and vertically - directed steam jets situated in a slotted opening in the top of the air chamber produce an outlet of air therethrough. The air supply may be heated in a chamber round the fire-door. This subject-matter does not appear in the Specification as accepted.